Sheet Conveyance State Detection via Motor Torque Analysis

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Solution Overview

Problem

Existing sheet conveying devices face challenges in accurately determining the sheet conveyance state and detecting deterioration of conveyance members, especially at the initial stages, due to small changes in the amount of movement per unit time, leading to inefficiencies and inaccuracies in determining the condition of sheet conveyance members.

Innovation Solution

A sheet conveying device is designed with a first sheet conveyor and a second sheet conveyor, along with a determiner that assesses the sheet conveyance state based on the torque of the motors driving the rollers, allowing for precise detection of sheet conveyance and member deterioration by analyzing the torque changes and sagging of sheets between the conveyance units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the amount of movement of sheet per unit time is used to determine sheet conveyance state, then the determination can be made based on simple measurement, but the detection precision is insufficient especially at initial stages of deterioration

Engineering Contradiction:
Improvedetection precision of sheet conveyance stateVSAvoidcomplexity of determination method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the measurement parameter from sheet movement amount to motor torque. By detecting torque changes in the motor driving the conveyance roller, the system can identify sheet conveyance state and deterioration with higher precision, especially in initial stages, without significantly increasing system complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical measurement methods (detecting sheet movement) with electrical measurement methods (detecting motor torque). This substitution enables more sensitive detection of conveyance state changes while simplifying the overall determination mechanism through electronic sensing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If multiple detection sections with non-overlapping time zones are used to calculate sheet movement ratio, then the productivity is improved through parallel detection, but the measurement precision deteriorates due to small changes in movement amount

Engineering Contradiction:
Improvedetection efficiencyVSAvoidprecision of deterioration detection
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The invention changes from measuring sheet movement amount to measuring motor torque directly. This parameter change enables high-precision detection of conveyance state without requiring multiple detection sections or complex ratio calculations, thus maintaining productivity while improving precision.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the sheet conveyance member deterioration is determined by comparing calculated ratio with reference value, then the determination process is simplified, but the reliability is reduced due to inability to detect initial stages of deterioration

Engineering Contradiction:
Improveaccuracy of deterioration detectionVSAvoidcomplexity of determination system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses motor torque as the detection parameter, which provides higher sensitivity to conveyance state changes. This enables reliable detection of initial deterioration stages while keeping the determination system relatively simple through direct torque measurement and comparison.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables accurate determination of sheet conveyance states and timely detection of conveyance member deterioration, improving the efficiency and reliability of the sheet conveying process by utilizing torque changes and sagging characteristics to assess the condition of the conveyance system.

Implementation Method 1

The first sheet conveyor is configured to interpose the sheet between the first sheet feed roller and the second sheet feed roller and convey the sheet to the second sheet conveyor as the first sheet feed roller rotates

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a conveyance roller, and a second motor configured to rotate the conveyance roller

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3674236B1Sheet conveying device and image forming apparatus incorporating the sheet conveying device
Publication Date: 2021.09.08 RICOH CO LTD
  • EP3674236B1 patent drawingFigure 1
  • EP3674236B1 patent drawingFigure 2
  • EP3674236B1 patent drawingFigure 3

AI summary

A sheet conveying device (200) includes a sheet pickup body (221), a first sheet conveyor (251, 255, 252), and a second sheet conveyor (271, 272), which are disposed in this order along a sheet conveyance direction, and a determiner (553). The determiner (553) is configured to determine a sheet conveyance state of a sheet based on at least one of torque of a first motor (252) of the first sheet conveyor (251, 255, 252) and torque of a second motor (272) of the second sheet conveyor (271, 272). The first sheet conveyor (251, 255, 252) is configured to interpose the sheet between a first sheet feed roller (251) and a second sheet feed roller (255) and convey the sheet to the second sheet conveyor (271, 272) as the first sheet feed roller (251) rotates.